Hurricanes, Tornadoes, Blizzards, Floods and Droughts

3. Form over warm, tropical ocean
waters.
Sometimes called typhoons (Asia)
Formed when air flows over warm
water (over 80 degrees), picking up
large amounts of moisture and
energy.
This flows into a low pressure core &
tightens to form the “eye” or center.
The more heat energy there is, the
stronger the winds become.

5.  Forms slowly over
days
 10-20 mile wide eye
 Can be up to 500
miles wide
 Classified by wind
speed in the Saffir-
Simpson scale;
category 1-5
 Winds from 75-200
mph
 Winds move counter-
clockwise (northern
hemisphere)
 Most storms start off
the coast of Africa and
move west (Cape Verde
storms)
 Damage includes
flooding, wind
damage, & storm surge.

10.  In 1992, Hurricane
Andrew, a
category 5
hurricane made
landfall in Florida.
 At the time, it was
the most costliest
hurricane in
history, causing
over $26 billion in
damages.

13.  Hurricane Katrina was
one of the most
deadliest and
devastating hurricanes
in recorded history.
 It was responsible for
1,800 deaths and over
$81 billion in damages,
making it the costliest
natural disaster in U.S.
history.

18.  Powerful funnel-shaped columns of spiraling
air.
 Warm air and cool air colliding create them
 Winds up to 300 mph.
 Measured on the Fujita Scale; 0-6.
 Generally they have small diameters (300 ft.)
and travel short distances (1 mile)
 3 out of 4 tornadoes in the world occur in the
U.S. (around 700 per year)

20. F1 Tornado
F2 Tornado
F3 Tornado F4 Tornado

21. F5 Tornado

23.  On May 22, 2011 a
catastrophic, multi-
vortex F5 tornado hit
the town of
Joplin, Missouri.
 It killed 158 people and
caused nearly $3 billion
in damages making it the
deadliest and costliest
tornado in American
history.

25.  Before
 After

31. Blizzard - Heavy snowstorm w/
winds of more than 35 mph
creating reduced visibility.
Floods - Water spreads out over
normally dry land
Droughts – A long period of time
w/o rain or minimal rainfall.
 - Droughts result in crop
failures, reduced levels of water in
storage.

34.  In 1993, a massive storm hit the
United States.
 Known as the “White
Hurricane”, this storm not only
caused a blizzard, but heavy
winds, rains and tornadoes.
 Many states received several feet
of snow. Tennessee got the worst
with over 5 ft. of snow in some
areas!
 In total, more than 300 people
died as a result of this storm.

38.  In 1993 a great flood
occurred in the Mississippi
River basin.
 The flood was among the
most costly and
devastating to ever occur
in the United States, with
$15 billion in damages and
effecting over 30,000
square miles.
 The floods claimed near
50 lives.
LANDSAT views of the Mississippi,
Missouri and Illinois Rivers.

40.  Drought is an extended
period of time when a region
has a deficiency in its water
supply whether surface or
underground water.
 A drought can last for
months or years.
 It can cause significant
damage[and harm on
the ecosystem, agriculture o
f the affected region as well
as damage to the economy.

41.  The Great Plains
(150,000 square mile
region) was ravaged by
drought.
 Thousands of families
were forced to flee and
find work elsewhere.
 Major contributor of the
economic disaster known
as the Great Depression
that took over 10 years
to recover from.

44.  In 2011, Texas was hit hard by
drought.
 The drought dried up areas so much
that in one town, it revealed some
old history.
 The city of Bluffton, Texas was
purposefully flooded more 50 years
ago to create Lake Buchanan.
 Many parts of town were submerged
under the 20-30 feet under the
lake, that is, until the drought.
 Since the drought, receding lakes
have been revealing the foundations
of buildings, streets and eerily, old
gravesites…